In a structure of a semiconductor light emitting device such as LED (light emitting diode), for instance, a crystal layer formed on a sapphire substrate is bonded to a conductive substrate, and then the sapphire substrate is removed (JP 2010-157579 A (Kokai)). In this structure, to increase the light extraction efficiency, unevenness is formed at the crystal layer surface exposed by removing the sapphire substrate. In such a semiconductor light emitting device, further improvement in the light extraction efficiency is desired.